COLLEGE STATION, Texas — Texas A&M shocked the college football world when it went into Tuscaloosa, Ala., and upset the No. 1 Alabama Crimson Tide last November. It was a game for the ages, with the Aggies jumping out to a 20-0 lead, Alabama charging back to make it close and a nailbiter finish that included a turnover near the goal line.

With the Crimson Tide coming to Kyle Field for a rematch with the Aggies, anticipation has built throughout the offseason. The Tide are again No. 1, defending their BCS championship from a year ago and the Aggies still have their linchpin, Heisman Trophy winner Johnny Manziel, who made his most compelling case for the trophy that afternoon at Bryant-Denny Stadium.

As the heavily hyped clash approaches, let's look back at some of the keys to last year's game and how they might affect the rematch.

1. Credit to the Texas A&M defense

When dissecting Texas A&M's upset of Alabama last season, many cite the Aggies' offensive explosion en route to a 20-0 first-quarter lead as one of the most difficult things for Alabama to deal with. And while the Aggies used creative playcalling and personnel packages, their fast pace and precision execution to score three touchdowns on their first three drives, the Aggies' defensive effort had as much -- or more -- to do with their ability to take that kind of commanding lead.

AJ McCarron threw his first interceptions of the season in Alabama's loss to Texas A&M last season. John David Mercer/US Presswire

The first play from scrimmage helped the Aggies set the tone as Alabama handed off to running back Eddie Lacy on an off-tackle play to the left side. Tight end Michael Williams motioned to that side of the formation to help open a hole for Lacy, but Texas A&M linebacker Sean Porter eluded Williams and sliced into the gap between Williams and left tackle Cyrus Kouandjio and made a strong tackle to stop Lacy for no gain. Alabama went three-and-out on that drive and punted.

The Crimson Tide's next offensive drive started on a much better note for Alabama, with Lacy gaining 23 yards on his first two carries. But everything halted as the Aggies created a turnover when quarterback AJ McCarron tried to find Kenny Bell in the middle of the field. As a McCarron pass hit Bell in the chest, safety Howard Matthews delivered a hard, clean hit to Bell, who dropped the pass. Porter was there to intercept the pass, and that set up the A&M offense with great field position after a 16-yard return to the Alabama 41.

One of the key players throughout the day for the Aggies' defense was defensive tackle Spencer Nealy. A former defensive end who moved to defensive tackle at the start of the 2012 season despite lacking what would be considered "SEC size" for a tackle, Nealy played an integral role in the Aggies' run defense. Evidence of that was on display at the start of the Crimson Tide's third drive of the game.

On the first play of the drive, Alabama handed off to T.J. Yeldon on the left side and the 6-foot-5, 277-pound Nealy, who lined up at nose tackle on that play and for much of the day, used his quickness to beat center Barrett Jones and tackled Yeldon for a loss of 4 yards. The Crimson Tide went three-and-out on that drive as well as the Aggies forced McCarron's hand with a safety blitz and Matthews got into the backfield untouched, forcing an incomplete pass. The defensive effort by the Aggies forced McCarron to start the game 1-of-5 passing for 5 yards.

And even though the Tide were able to gather their bearings and make a strong comeback with some big plays on offense, the Aggies still found ways to make plays on defense. Matthews plugged a gap on third-and-2 when Yeldon tried to cut back for first-down yardage, holding the Crimson Tide to a third-quarter field goal. Safety Steven Terrell stripped Yeldon in the fourth quarter on the play after a 50-yard pass from McCarron to Amari Cooper. And of course, cornerback Deshazor Everett picked off McCarron on the Tide's final offensive play with 1:36 remaining.

The drawback for Texas A&M in the rematch is that many of the above names are gone. Nealy, Porter, Terrell and other key players -- such as defensive end Damontre Moore and linebacker Jonathan Stewart -- have graduated. They've been replaced by younger, more inexperienced players who have taken their lumps in the first two games. The Aggies also haven't had their full complement of defensive players because several served suspensions in the first two games. Saturday will be the first opportunity for all of their key guys to play together this season.

Lacy is gone for the Tide, as are several offensive linemen. The Tide struggled in that area in their season-opening win against Virginia Tech. So there will be adjustments on both sides with the differences in personnel.

2. Finding the "Y"

Manziel went to receiver Ryan Swope, the "Y" receiver who lines up in the slot on the right side of the offensive formation, early and often against the Crimson Tide. Early in the game the passes were of the short, quick variety, hitch routes that gained incremental yardage, almost like running plays.

As the game wore on, Manziel went downfield to Swope, who made some of the biggest catches of the season. One was in the middle of the field for 28 yards as he was nailed by safety Ha Ha Clinton-Dix in the third quarter. In the fourth, Manziel found Swope down the right sideline for 42 yards.

Swope graduated as well, but look for the guy who made the catch on the play after Swope's 42-yard reception -- Malcome Kennedy -- to be a factor. Kennedy caught a 24-yard touchdown pass on the next play and having experience in a game like that can only help him this Saturday. The question is, can Kennedy bring the kind of consistency that Swope did in catching 11 passes for 111 yards and a touchdown against Alabama?

And should he be healthy for the game, 6-foot-5 freshman receiver Ricky Seals-Jones could be a factor at that position as well. Seals-Jones missed the Sam Houston State game last Saturday with a knee injury.

3. McCarron can scramble, too

While Manziel is known for his scrambling, McCarron showed he has good mobility as well.

McCarron isn't nearly as fleet of foot, but he did show the ability to escape pressure and make quality throws. On two instances in the Crimson Tide's first scoring drive, he evaded the Aggies' pass rush and found Cooper for a first-down completion.

In the second half, McCarron scrambled and tried to find Cooper. He avoided an interception from Everett (who was ruled out of bounds on the catch), but nevertheless, scrambling is a tool McCarron can use if the Aggies dial up extra pressure Saturday.

4. Defending Manziel on the ground

Johnny Manziel had great success running in the first half against Alabama, but the running lanes closed a bit in the second half. AP Photo/Dave Martin

In the first half last year, Manziel was electric with his feet. Then-offensive coordinator Kliff Kingsbury was comfortable in calling designed quarterback draws. They were successful as Manziel piled up 82 yards on nine first-half carries.

But the Tide did a much better job containing Manziel in the final two quarters. In the second half, he finished with 10 rushing yards on nine attempts.

This season, Manziel is making an effort to improve as a pocket passer without taking away his playmaking ability. The Aggies have a new offensive coordinator and playcaller (Clarence McKinney) and a new quarterbacks coach (Jake Spavital). It will be interesting to see how much running Manziel does Saturday and how Alabama handles it.

5. Big plays in the Alabama passing game

Cooper, now a sophomore for the Tide, had a huge game in last year's matchup, catching six passes for 136 yards.

He had a catch of 50 yards and a 54-yard touchdown reception, both in the fourth quarter. The first came on an out-and-up, when he beat Everett one on one. The next one came when the Aggies sent Everett on a cornerback blitz and Cooper beat Matthews deep for a touchdown.